GB2372862A

GB2372862A - A distributed vehicle occupant restraint system

Info

Publication number: GB2372862A
Application number: GB0126481A
Authority: GB
Inventors: Steven Yellin Schondorf; Rene A Najor; Troy Otis Cooprider
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2000-11-15
Filing date: 2001-11-05
Publication date: 2002-09-04
Also published as: DE10153052A1; GB0126481D0

Abstract

An occupant restraint system having a crash detection signal, a plurality of satellite restraint modules receiving diagnostic signals from an associated restraint, such as air-bags and seat-belt pre-tensioners, and an occupant condition signal from sensors. These signals are transmitted to a control module that determines whether a restraint is to be triggered by sending an activation signal to the appropriate satellite module. This may trigger the squib of an air bag, or cause the seat-belt pre-tensioner to tighten. Furthermore the system alerts the occupant to the status of the restraint.

Description

A DISTRIBUTED RESTRAINT SYSTEM

This invention relates to occupant restraint systems for automotive vehicles, and more specifically to a control system architecture that provides increased flexibility and growth capability in the design of such restraint systems.

Seatbelts and airbags are used in automotive vehicles to prevent severe injuries to the vehicle occupants during collisions with other objects. In some current vehicles, the airbags and/or seatbelts pre-tensioners form part of an occupant restraint system which includes a restraint control module (RCM).

The RCM comprises a microprocessor or integrated circuit that receives electronic inputs from a variety of sensors, such as crash sensors and occupancy sensors, and triggers the airbags and/or belt pre-tensioners as required in response to a crash event.

In first-generation airbag systems, the RCM triggers each airbag by sending a 12 volt D. C. firing pulse to an electrical igniter or squib. The squib ignites a pyrotechnic device that produces gas to inflate the airbag.

A more recent proposed airbag system utilizes what is known as a remote firing bus, wherein a master integrated

circuit (IC) in the RCM is in two-way, digital communication with a slave IC co-located with each airbag squib.

The RCM receives inputs from the slave IC such as airbag diagnostic and identification information. When the RCM concludes that a crash event has occurred and has decided which of the airbags should be deployed, the master IC sends a digital"deploy"signal to the appropriate slave ICs, causing them to send a firing pulse to the squibs to inflate the bags. An example of a restraint system

utilising such a remote firing bus is disclosed in U. S.

Patent No. 5, 882, 034. Modifying an occupant restraint system to utilize this remote firing bus system requires a complete re-design of the RCM and the activation portions of the restraints.

Various models of a particular vehicle type or platform may be constructed with varying numbers of restraints, depending on the specific vehicle configuration. For example, a van, station wagon or sport utility vehicle (SUV) may be constructed with or without a third row of seats and associated restraints. As another example, restraint systems for other than the front seat occupants may be optional equipment.

In yet another example, a particular type of vehicle may initially enter production with a given number of restraints, with the plan to increase the number in future production model years.

In any of these cases, it would be advantageous if a standard RCM could be used in the vehicle platform, with accommodation made for simple and inexpensive expansion of the system capability to handle an increase in the number of restraint and associated occupant condition sensors.

As the number of restraints in an occupant safety system increases, the number of required connections with the RCM also increases. For at least some of the seating positions, the RCM will also receive inputs from one or more occupant condition sensors, such as a seatbelt status sensor, a seat occupant weight sensor, or a seat track position sensor. If one or more occupant condition sensor inputs are provided to the RCM for each of the seating positions, the number of electrical connections to the RCM may become very large, requiring a connector with a large

number of pins and which therefore takes up a significant amount of space.

It is an object of this invention to provide a system architecture for an occupant restraint system that allows a restraints control module (RCM) to be used as a universal component in the restraint systems of a range of vehicles having different numbers and types of individual restraints.

According to the invention there is provided an occupant restraint system comprising a central restraint control module operable to receive a signal from a crash sensor indicative of a crash event and a number of satellite restraint modules operable to receive diagnostic signals from at least one associated restraint and an occupant condition signal and arranged to communicate this information to the central module wherein the central module makes a restraint activation decision based at least in part upon the occupant condition signals and generates an activation signal that is transmitted to the or each satellite module causing the satellite module to provide a trigger pulse to the restraint.

There may be a number of seating positions and an occupant restraint is associated with at least one of the seating positions, an occupant condition sensor is associated with the respective seating position to generate an occupant condition signal, at least one crash sensor is provided for monitoring kinematic parameters relating to the and arranged to generate a kinematic signal indicative of the sensed parameter, a respective satellite restraint module connected with the occupant condition sensor to receive the occupant condition signal and connected with the restraint associated with the at least one seating position to perform a diagnostic check on the restraint and to provide a triggering pulse to the restraint and a central restraints control module receiving the kinematic signals

from the crash sensor, receiving the occupant condition signal from the satellite restraint module, making an activation decision for the restraint based at least in part upon the kinematic signals and the occupant condition signal, generating an activation signal, and transmitting the activation signal to the satellite restraint module to cause the satellite restraint module to provide the triggering pulse to the restraint.

Several seats may have a restraint and an occupant condition sensor associated therewith.

Each satellite module may be associated with a single seat.

Alternatively, at least one satellite module may be associated with more than one seat.

At least one crash sensor may be an inertial sensor or may be a predictive sensor.

Each satellite restraint module may relay results of the diagnostic check to the central restraints control module and the central restraints control module may perform a fault management operation.

In which case the central restraints control module may generate a notification message for display to vehicle occupants in order to alert the occupants of the status of the restraint.

The restraint may include a pyrotechnic device and the triggering pulse may ignite a squib of the pyrotechnic device.

In which case the restraint may further include an airbag and the pyrotechnic device may generate gas to inflate the airbag.

The airbag may have at least two different stages of inflation and the activation signal will result in either of the two stages of inflation.

Alternatively, the restraint may comprise a seatbelt having a pre-tensioning device, the triggering pulse causing the pre-tensioning device to tighten the seatbelt.

The occupant condition sensor may comprise at least one of the following a seatbelt status sensor, a seat occupant weight sensor, a non-contact seat occupant position sensor, or a seat track position sensor.

The satellite restraint module may include a back-up electrical power supply to permit sending of the triggering pulse in the event that the satellite restraint module ceases to receive power from a main vehicle power system.

The satellite restraint module may be integrated with an independently functioning vehicle electronic component.

The vehicle electronic component may be an instrument cluster or may be an occupant condition sensor.

The invention will now be described by way of example with reference to the accompanying drawing of which : Figure 1 is a schematic diagram of a vehicle equipped with an occupant restraint system according to a first embodiment of the invention; Figure 2 is a block diagram depicting the overall system architecture of an occupant restraint system

according to a second embodiment of the present invention ; and Figure 3 is a block diagram depicting in greater detail the functionality of a central restraints control module and a satellite restraint module according to the invention.

Referring to Figure 1, a vehicle 10 is shown fitted with an occupant restraint system in accordance with the teachings of a preferred embodiment of the invention.

The system comprises a central restraints control module (CRCM) 12 serving as a main control center for the system, and a plurality of satellite restraint modules (SRMs) 14a-d interfacing with restraints 16a-c and occupant condition sensors 18a-d.

The CRCM 12 receives signals from a plurality of crash sensors 20-26 mounted at various locations within the vehicle, processes and utilizes the received signals to determine whether a crash is occurring or is about to occur, and selectively instructs activation or deployment of the various restraints 16a-c in view of signals from the restraints and occupant condition sensors 18a-d that are relayed to the CRCM 12 by the SRMs 14a-d.

The CRCM 12 is of a fairly conventional design and includes one or more microprocessors and integrated circuits which control the operation of system and includes permanent and temporary memory which stores at least a portion of the operating software and crash detection algorithms used to direct the operation of CRCM 12.

The CRCM 12 also selectively stores other types of data or information, including information associated with the operation of the system such as historical data, processing data, and operational data.

The CRCM 12 also performs safety functions for the restraints to ensure that unintended deployments of the restraint do not take place, and is provided with safety sensors (not shown) as necessary.

It will be apparent to those of ordinary skill in the art, that although the CRCM 12 is described herein as a single unit it could comprise a plurality of commercially available, conventional, and disparate chips or devices operatively linked with one another.

The crash sensors used are conventional and commercially available inertial crash sensors for detecting vehicle acceleration and/or rollover about any of the vehicle axes.

Figure 1 depicts a combination longitudinal acceleration and rollover sensor 20 mounted in the tunnel area between the front seats, door-mounted impact sensors 22 for measuring lateral acceleration at each of the four doors, and crush sensors 24 mounted on the front bumper to detect deformation. If required one or more inertial crash sensors can be integrated with and co-located with CRCM 12.

A predictive crash sensor 26 may also be used with the present invention and may, for example, be a radar system, an ultrasonic system, a vision system, a laser system, or other appropriate systems as are well known in the art.

Each SRM 14a-d is preferably associated with a particular seating position within the vehicle, for example the driver seat, the front passenger seat, or a rear seat position, and is further in electrical communication with one or more restraints and occupant condition sensors associated with the seating position.

The front seat SRM 14a is integrated with an electronic instrument cluster 17 located in front of the driver position and the passenger SRM 14b is shown integrated with an pressure sensing mat in the passenger seat.

The rear seat SRMs 14c, 14d are shown as stand-alone units disposed in the seat backs of the front seats adjacent their respective seating positions.

Each SRM 14a-d connected with one or more occupant condition sensors, examples of such occupant condition sensors, as shown in Figure 1, include seatbelt status sensors 18a, seat weight sensors 18c on the passenger seat and rear seats, a seat position sensor 18b mounted on the driver seat track, and a non-contact position sensor 18d for the passenger seat.

Several types of non-contact position sensors are well known in the advanced restraint arts and use various sensing techniques to detect occupant size and/or position, such as ultrasonic, infrared, or capacitive sensing.

Each SRM 14a-d is also connected with one or more restraints 16a-c associated with its seating position.

The SRMs 14a-d are each connected with a front airbag 16a, a side airbag 16b, and a seatbelt pre-tensioner 16c.

The restraints are powered by pyrotechnic gas generators (not shown) that are ignited by electrically triggered squibs (not shown). Alternatively, the airbags 16a, 16b could be inflated by cold gas, and/or the seatbelt pre-tensioners 16c may be actuated by electric motors as is known in the restraints art.

In Figure 2 an occupant restraint system configured somewhat differently from that of Figure 1. is shown in block diagram form.

A driver seat SRM 14a is connected with a front airbag 16a, a side airbag 16b, a belt pre-tensioner 16c, an inflatable rollover curtain 16d, a seatbelt status sensor 18a, a seat weight sensor 18c, a seat position sensor 18b, and a non-contact occupant sensor 18d.

It should be noted that Figure 2 depicts a system wherein the entire second row seating is provided with a single SRM 14e interfacing with all occupancy sensors and restraints used in the row, and similarly the third row seating uses a single SRM 14f. Such a configuration may be desirable depending upon the number and type of restraints provided in the vehicle and the overall control architecture.

The invention system architecture allows a high degree of flexibility in the configuration of the number, type, and location of restrains and occupancy sensor making up the system.

Figure 3 depicts in more detail the information transfers between the CRCM 12 and a SRM 14, an airbag 16, and an occupant condition sensor 18.

For simplicity of description, Figure 3 depicts only a single airbag and a single occupant condition sensor associated with the SRM 14, and the following description deals with only these components. It is to be understood, however, that multiple restraints and/or occupancy sensors may be associated with a particular SRM, as depicted in Figures 1 and 2.

The occupant condition sensor 18 transmits an occupant condition signal to the SRM 14, the signal containing information related to the particular occupant status parameter being monitored by the occupant condition sensor.

For example, a seatbelt status sensor transmits a signal indicating whether or not the buckle is fastened and/or how much of the seatbelt length is pulled off of the reel, a seat weight sensor transmits a signal indicating the amount of weight present on the seat, a seat position sensor transmits a signal indicating the fore and aft position of the seat, etc. The occupant condition sensor 18 also transmits a diagnostic signal to the SRM 14 indicating whether the occupant condition sensor 18 is functioning properly and identifying faults that may hamper its correct operation.

The airbag 16 transmits an airbag diagnostic signal to the SRM 14. The airbag diagnostic signal may indicate, for example, the resistance value of the airbag squib ignition circuit to enable detection of shorts or other wiring faults in the airbag or associated wiring.

The occupant condition sensor diagnostic signal, occupant condition signal and airbag diagnostic signals are relayed from the SRM 14 to the CRCM 12, which serves as the diagnostic centre for the system.

The CRCM 12 uses the diagnostic information to perform failure mode management. One or more restraint status indicators 30 are preferably provided in the passenger compartment to alert the vehicle operator to system failures detected by the CRCM 12.

As is well known in the restraints art, the CRCM 12 uses the signals from crash sensors 32 as inputs to a crash decision algorithm to determine when a crash event has occurred or is about to occur, and for which it is necessary

to deploy or activate the vehicle restraint systems. In making the decision as to what restraints should be deployed and in what mode, the CRCM 12 considers inputs from the occupant condition sensors 18 as relayed via the SRMs 14.

For example, if the crash determination algorithm indicates a frontal collision, the CRCM 12 is operable to cause deployment of front airbags. If the occupant condition signal for a seating position indicates a small individual and/or an individual seated relatively close to the airbag, the CRCM 12 may suppress deployment of the airbag or, in the case of a dual-stage airbag, instruct a lower powered first-stage inflation of the airbag. If the occupant condition signal indicates a large and/or unbelted individual to be present in the seating location, the CRCM 12 may, for example, order a more powerful and/or rapid second-stage inflation of the airbag.

Upon determining which restraints to deploy and in what manner, the CRCM 12 transmits deployment signals to the appropriate SRM 14. A deployment signal is a coded digital signal rather than a simple DC pulse, making it extremely unlikely that a simple electrical malfunction will cause inadvertent or incorrect deployment of a restraint. The deployment signal includes instructions as to which restraints to deploy and, if necessary, in what mode the restraints are to be deployed.

When the SRM 14 receives the deployment signal, it transmits triggering pulses to the appropriate restraint or restraints, causing them to deploy in the desired manner.

As is well known in the airbag art, the triggering pulse for an airbag is typically a 12-volt, 1.2 amp D. C. pulse with a duration of approximately 3 milliseconds.

The SRM 14 is connected directly to the main vehicle electrical system 34 to receive power for the triggering pulse but preferably includes a back up power supply in the form of a capacitor 36 or other electrical energy storage device so that it can still generate a triggering pulse if it is disconnected from the main vehicle electrical system by a malfunction, such as may occur during a crash.

The electrical connections between the CRCM 12 and the SRM 14 may take the form of a single twisted-pair of wires, with multiplexing used to carry the required number of digital signals over the common connection. Alternatively, multiple wires and/or twisted-pairs may be provided to achieve the desired connectivity.

As described above in connection with Figure 1, it is possible for the SRM 14 to be integrated into another vehicle electronic component, such as an instrument cluster or an occupant condition sensor, or the SRM 14 may be a stand-alone unit.

As may be seen from the above description, an occupant restraint system according to the invention may be adapted to permit nearly any number of satellite restraint modules to be connected with a central restraint control module so that a restraint system can be reconfigured and/or expanded as necessary to accommodate different numbers of deployable restraints without making substantial changes to the CRCM 12 or the restraint deployment initiators.

Those skilled in the art will appreciate that numerous variations and modifications could be made to the specific embodiments described herein without deviating from the scope of this invention.

Claims

Claims

1. An occupant restraint system comprising a central restraint control module operable to receive a signal from a crash sensor indicative of a crash event and a number of satellite restraint modules operable to receive diagnostic signals from at least one associated restraint and an occupant condition signal and arranged to communicate this information to the central module wherein the central module makes a restraint activation decision based at least in part upon the occupant condition signals and generates an activation signal that is transmitted to the or each satellite module causing the satellite module to provide a trigger pulse to the restraint.

2. An occupant restraint control system as claimed in claim 1 wherein there are a number of seating positions and an occupant restraint is associated with at least one of the seating positions, an occupant condition sensor is associated with the respective seating position to generate an occupant condition signal, at least one crash sensor is provided for monitoring kinematic parameters relating to the and arranged to generate a kinematic signal indicative of the sensed parameter, a respective satellite restraint module connected with the occupant condition sensor to receive the occupant condition signal and connected with the restraint associated with the at least one seating position to perform a diagnostic check on the restraint and to provide a triggering pulse to the restraint and a central restraints control module receiving the kinematic signals from the crash sensor, receiving the occupant condition signal from the satellite restraint module, making an activation decision for the restraint based at least in part upon the kinematic signals and the occupant condition signal, generating an activation signal, and transmitting the activation signal to the satellite restraint module to

cause the satellite restraint module to provide the triggering pulse to the restraint.

3. A system as claimed in claim 2 wherein several seats have a restraint and an occupant condition sensor associated therewith.

4. A system as claimed in claim 2 or 3 in which each satellite module is associated with a single seat.

5. A system as claimed in Claim 2 or in Claim 3 in which at least one satellite module is associated with more than one seat.

6. A system as claimed in any of claims 1 to 5 wherein each satellite restraint module relays results of the diagnostic check to the central restraints control module and the central restraints control module performs a fault management operation.

7. A system as claimed in claim 6 wherein the central restraints control module generates a notification message for display to vehicle occupants in order to alert the occupants of the status of the restraint.

8. A system as claimed in any of claims 1 to 7 wherein the restraint includes a pyrotechnic device and the triggering pulse ignites a squib of the pyrotechnic device.

9. A system as claimed in claim 8 wherein the restraint further includes an airbag and the pyrotechnic device generates gas to inflate the airbag.

10. A system as claimed in claim 9 wherein the airbag has at least two different stages of inflation and the activation signal will result in either of the two stages of inflation.

11. A system as claimed in any of claims 1 to 7 wherein the restraint comprises a seatbelt having a pre tensioning device, the triggering pulse causing the pretensioning device to tighten the seatbelt.

12. A system as claimed in any of claims 1 to 11 wherein the satellite restraint module includes a back-up electrical power supply to permit sending of the triggering pulse in the event that the satellite restraint module ceases to receive power from a main vehicle power system.

13. A system as claimed in any of claims 1 to 12 wherein the satellite restraint module is integrated with an independently functioning vehicle electronic component.

19. An occupant restraint system substantially as described herein with reference to the accompanying drawing.